DHCP:动态主机配置协议
基于udp的 监听端口 客户端：68(dhclient) 服务端：67(dhcpd)
地址租约信息：/var/lib/dhcpd/dhcpd.leases
租约：
ip地址租约约定：ip用的租期的50%时客户端必须向服务器提出续约的请求，若失败则会用剩下的一半时间即75%再向服务器请求，一般到87.5%再请求不到ip会收回
进程为：dhcpd
配置文件：/etc/dhcpd.conf
辅助配置文件：/etc/sysconfig/dhcpd
服务脚本: /etc/init.d/dhcpd start|stop|restart
样例配置文件：/usr/share/doc/dhcp-3.0.5 /dhcpd.conf.sample
出现同一选项是以自由选项为准 作用范围小优先级高
配置DHCP服务器：
前提：
关掉selinux
虚拟机中关掉自身的dhcp
网卡使用hostonly 配置其ip
配置文件：/etc/dhcpd.conf
ddns-update-style interim; dhcp支持的dns动态更新的方式
ignore client-updates; 不允许客户端更新dns记录
subnet 192.168.20.0 netmask 255.255.255.0 {
# --- default gateway
option routers 192.168.20.1; 网关
option subnet-mask 255.255.255.0;
# option nis-domain "domain.org"; nis验证域名
option domain-name "example.com"; 动态域名
option domain-name-servers 100.100.10.1,200.200.20.2; dns服务器
option time-offset -18000; # Eastern Standard Time
# option ntp-servers 192.168.1.1;
# option netbios-name-servers 192.168.1.1;
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
# option netbios-node-type 2;
range 192.168.20.4 192.168.20.25; 允许分配的地址池
default-lease-time 21600; 租约时间
max-lease-time 43200; 租约最大时间
# we want the nameserver to appear at a fixed address
host ns { 主机ip的绑定
hardware ethernet 00:0C:29:F5:29:21; 主机mac地址
fixed-address 192.168.20.40; 主机ip
}
}
默认监听每个网卡：0.0.0 .0
监听特定网卡地址：/etc/sysconfig/dhcpd配置
DHCPDARGS=eth0
客户端动态获得地址：
dhclient eth0
参数-d 测试会显示获得过程 ctrl +c 取消
要重新获得地址要killall dhclient
使用自己规定的dns服务器在/etc/sysconfig/network-scripts/ifcfg-eth0 添加PEERDNS=no
定义地址类别：
基于mac地址的
基于操作系统的
class "vmware" {
match if substring (hardware, 1, 3) = 00:0C:29;
}
class "microsoft-client" {
match if substring (option vendor-class-identifier, 0, 3) = "MSFT";
option routers 192.168.0.254
option domain-name-servers 100.100.10.1,200.200.20.2;
}
pool {
allow members of "vmware";
range 192.168.20.40 192.168.20.60;
}
pool {
deny members of "vmware";
deny members of "microsoft-client";
range 192.168.20.100 192.168.20.120;
}
中继器代理的应用:实现不同网络段的ip的分配
/etc/sysconfig/dhcrelay
INTERFACES="eth0 eth1" 实现网段的接口即网卡接口
DHCPSERCERS="192.168.20.5" dhcp服务器地址
开启服务server dhcrelay restart
服务器的配置：/etc/dhcpd.conf 添加
subnet 192.168.100.0 netmask 255.255.255.0 {
option routers 192.168.100.1;
option subnet-mask 255.255.255.0;
range 192.168.100.60 192.168.100.70;
}
